Golf balls are generally formed with a multiplicity of dimples of circular plane shape on their surface in order to improve their aerodynamic characteristics. It is well known that the dimpled golf balls fly better than dimple-free golf balls having a smooth spherical surface.
The flight distance of golf balls is dictated by many factors including the initial velocity and spin rate of the ball, drag and lift acting on the ball in flight, and weather conditions. It has been considered difficult to make theoretical analysis on golf balls with the aim of increasing their flight distance.
For improving the flight performance of the ball except for the initial velocity which is largely governed by the material of the ball, a number of attempts of tailoring dimples relating to the geometrical factors of the ball have been made. Such attempts include, for example, increasing the diameter of dimples, using plural types of dimples having different diameters, increasing or decreasing the depth of dimples, changing the shape of dimples from circular one to polygonal and other shapes, and increasing or decreasing the number of dimples. Certain improvements have been made.
None of these attempts succeeded in developing a golf ball having satisfactory flight performance when judged from the skill level of professional golfers. Further improvement and development of golf balls are desired.